Reflective barndoor

ABSTRACT

A soft fill luminaire for minimizing shadows on the field to be illuminated is provided with reflective barndoors. The barndoors raise the level of fill illumination at the center of the field without materially reducing the fill illumination at the margins of the field.

United States Patent Hamilton et a]; Jan. 1, 1974 1 REFLECTIVE BARNDOOR1,805,886 5/1931 Rizer 240/41.1 1,913,517 6/1933 Smith et a1.. 240/41.1[75] Inventors: f 'f' Los Angeles; 685,806 11 1901 Weber 240/75 RichardGllckman, Sherman 1,747,754 2/1930 Craig 240/3 Oaks; George t CanOga3,643,079 2/1972 Glickman 240/3 Park; Joseph N. Tawil, Woodland Hills,all of Calif.

[73] Assignee: Berkey-Colortran, lnc., Burbank, Primary Examiner-RichardSheen Calif Attorney-Fred Flam [22] Filed: July 7, 1972 [21] Appl. No.:269,709 I [57] ABSTRACT [52] US. Cl. 240/3, 240/4l.l5 [51] F2lp 5/00 ASoft fill luminaire for minimizing shadows on the [58] Field of Search240/3, 3.1, 41.1, fi to be illuminated is prbvided with reflective2410/4115 41 2 doors. The barndoors raise the level of fill illuminationat the center of the field without materially reducing [56] Referen eCit d the fill illumination at the margins of the field.

UNITED STATES, PATENTS 1,765,957 6/1930 Westphalen 240/3 3 Claims, 5Drawing Figures PATENTEDJAN 1 1974 SHEEI 1 0F 2 o 9 o wmwmwwmmo arm/veFee/w z w FEET PATENTEU JAN 1 74 SHEEI 2 OF REFLECTIVE BARNDOOR 1. Fieldof Invention i This invention relates to lighting'equipment suitable formotion picture and television photography or the like. The objectsintended to be photographed may be illuminated by the use of two typesof lighting equipment: first, primary or key lighting that brings thefield to a level of illumination appropriate for camera use; and second,fill lighting. Fill lighting may be used for two essentially difierentpurposes. One purpose is to highlight portions of the field. Anotherpurpose is to soften harsh shadows produced by the primary lightingequipmentfThis invention relates particularly to fill lighting of thetype intended to soften the field.

2. Discussion of Prior Art I Typical luminaires for providing ashadowless light comprise a rather large non-focusingreflector-illuminated by anindirect or recessed light source. If theshadows cast by theprimary light source were not sufficiently softenedby a single soft fill luminaire, addi- -tional similar luminaires werebrought into play. A

BRIEF SUMMARY OF THE INVENTION In order to achieve the foregoingobjective, we pro vide barndoor type attachments to the soft fillluminaire. Whereas barndoors are ordinarily black and nonreflective,serving onlyrsharply to cutoff primary lightingffrom edge portions ofthe field, the barndoors that we provide have their interior surfacesreflective. The light energyis redirected rather than absorbed, as inthe conventional barndoor arrangement. The intensity level ofthecentralportion of the field. is raised in a shadowless manner.

To the extent that one barndoor intercepts light energy that wouldilluminate the marginal portions of the field, .the opposite barndoor,by virtue of its reflective function, largely compensates. Consequently,the fill characteristics of the luminaire at the marginal field portionsare retained. Although the center of the field is more intenselyilluminated, it is illuminated by a source that does not increase theshadow-casting characteristic.

BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of the.invention will be'made with reference "to the accompanying drawings.These drawings, unless described as diagrammatic or unless otherwiseindicated,"are to Scale.

FIG. 1 is a diagrammatic view of a typical stage, indicating both aprimary lighting luminaire and a soft fill luminaire, the softfillluminaire being made in accordance with the present invention.

FIG. 2 is a graph showing intensity in foot candles of a conventionalsoft fill luminaire and a luminaire made in accordance with the presentinvention.

FIG. 3 is a front elevational view of the improved soft fil luminaire yFIG. 4 is a top plan view, thereof. FIG. 5 is an enlarged fragmentaryelevational-view showing a typical bracket mounting for the barndoor.

DETAILED. DESCRIPTION The following detailed description is of the bestpresently contemplated mode of carrying out the invention. Thisdescription is not to be taken in a limiting sense but ismade merely forthe purpose of illustrating the general principles, of the inventionsince the scope of the invention is best defined by the appended claims.In FIG. 1 there is illustrated a stage illuminated by one or moreprimarylighting luminaires 10. While the primary luminaire 10 raises the levelof illumination adequately for motion picture or television camera work,it casts sharp shadows due at least in part to thefact that the sourceitself is exposed along the axis of the luminaire opening and due inpart to the small physical size of an intense source. In order'to softenthe shad ows, a soft fill luminaire 1 2 provided.

The luminaire 12 includes a box-like housing 14 that has a largerectangular frontal opening 16. A source of illumination is locatedalong the bottom of the housing 14, and it is shielded from direct viewby a cover plate 18. The light from the source is cast upwardly towardsa reflector 20 formed in this instance on the inside of the housingback. The reflectorcasts soft fill lighting outwardly of the opening 16.

The illumination is of the shadowless type due to the indirect locationof the illumination source, the large size of the opening 16 and thebroad, non-focusing characteristics of thereflector 20. The graph A inFIG. 2 shows the distribution of illumination cast by the luminaire 12as thus far described.

' Without changing the 'size' or rating of the light source itself, thelevel of illumination at the center of thefield illuminated by theluminaire 12 is increased without markedly reducing the level ofillumination at the marginsof the field, allas indicated by the graph Bin FIG. 2. This'is accomplished by providing two barndoors 22 and 24 ating 14. r

The inner surface of each barndoor does not absorb light cast upon it asa conventional barndoor does, but instead redirects theluminousenergy tothe field to be opposite sides of the. luminaire housphotographed.Forthis purpose, the inner surface of each of the barndoors isreflective. The surface may be highly specular or mirror-like orpreferably it is slightly mottled. Each barndoor at least partiallyreiterates the illuminated luminaire housing, not the recessed lightsource itself. Each barndoor is located at an appropriate angle tointercept thelight radiating from the reflector 20 and to redirect it tothe center of the field.

The barndoor 24, for example, necessarily intercepts the soft fillillumination at the-right portion R of the stage. However, the companionbarndoor 22 reflects light from the luminaire 12 to the right portion ofthe stage past the edge of the barndoor 24.8imilarly, the barndoor 24compensates-for the intercept of the barndoor 22. Asshown in FIG. 2, themarginal illumination is not appreciably reduced by the barndoors 22 and24. In order to ensure the compensating effect, the width of thebarndoors is heldto a fraction of the width of the luminaire opening 16itself. Good results are achieved by limiting the barndoor width toabout one-half the width'of the opening 16.

The soft fill illumination at the center of the field is markedlyincreased by the reflective character of the barndoors, and the use of asecond soft fill luminaire may be avoided.

The configuration barndoors 22 and 24 is otherwise noncritical. Thedoors 22 and 24 may be supported in any desired manner to provideadjustment of angularity for focusing. In the present instance, thebarndoors are generally rectangular. A long, generally U-shaped bracket26 is attached to the inside of the barndoor 22 near one vertical edge.The ears 28 and 30 of the U- shaped bracket are pivotally mounted by apair of angle brackets 32 and 34. One of the brackets 34 is shown indetail in FIG. 5. The ear 30 is in face-to-face contact with theupstanding arm of the angle bracket 34. A screw 36 extends throughaligned apertures in the ear 30 and the bracket arm and is confined inthe apertures by a nut 38. A spring 40 surrounds the bold and actsbetween the head of the bolt 36 and the car 30 to impose a forceyieldingly restraining angular movement of the barndoor. The companionear 28 of the bracket 26 is similarly supported by the angle bracket 32.The com panion barndoor 24 is supported in the same manner.

Adjustment of the angularity of the barndoors serves to some extent toshape the curve B. For example, the center peak may be flattened and theperipheral level slightly raised. The angularity necessary to focus isof course a function of the distance of the luminaire from the subjectilluminated.

Intending to claim all novel, useful and unobvious features shown ordescribed,

We claim: 1. In a system of stage lighting in which one or moreluminaires provide primary lighting for the field to be illuminated, thecombination therewith of a separate secondary soft fill luminaire:

a. said soft fill luminaire having a housing providing a large openingadapted to be addressed to the field;

b. said housing having a reflector surface located behind said opening;

c. a source of indirect illumination frontally concealed within theopening, and casting light on said reflector; said luminaire having noeffective direct source of illumination; and

d. a pair of reflective members, each of said members being pivotablyattached on an opposite side of said large opening and being pivotableabout said side to an angle for concentrating illumination at the centerof the field illuminated by said soft fill luminaire, each of thereflective members compensating by reflection for the barndoor effect ofthe opposite reflective member whereby marginal illumination of thefield is maintained.

2. The combination as set forth in claim 1 in which said reflectivemembers are mounted for angular adjustment for focusing the reflectedrays.

3. The combination as set forth in claim 1 in which the width of eachreflective member is about half the corresponding width of the luminaireopening.

1. In a system of stage lighting in which one or more luminaires provideprimary lighting for the field to be illuminated, the combinationtherewith of a separate secondary soft fill luminaire: a. said soft fillluminaire having a housing providing a large opening adapted to beaddressed to the field; b. said housing having a reflector surfacelocated behind said opening; c. a source of indirect illuminationfrontally concealed within the opening, and casting light on saidreflector; said luminaire having no effective direct source ofillumination; and d. a pair of reflective members, each of said membersbeing pivotably attached on an opposite side of said large opening andbeing pivotable about said side to an angle for concentratingillumination at the center of the field illuminated by said soft fillluminaire, each of the reflective members compensating by reflection forthe barndoor effect of the opposite reflective member whereby marginalillumination of the field is maintained.
 2. The combination as set forthin claim 1 in which said reflective members are mounted for angularadjustment for focusing the reflected rays.
 3. The combination as setforth in claim 1 in which the width of each reflective member is abouthalf the corresponding width of the luminaire opening.